The study will address a critical challenge regarding the public health threat of synthetic psychoactive drugs (SPDs): identifying and characterizing how social media is used to market, distribute and sell these products to the public. We will carry out these aims by examining large volumes of data from popular social media platforms Twitter and Instagram using an innovative methodology involving machine learning and multidisciplinary data analysis. This research project addresses a key NIDA research objective: ?research on factors which influence initiation, continuation and desistance of use of specific SPDs in different populations. Examples include:?market and distribution factors; policies; and the role of peer influences, social media and the internet.? We will first collect large volumes of data filtered for SPD drug diversion, marketing, and drug dealing via social media posts, comments, and other messages. We will then code the data using an advanced machine learning protocol. Finally, we will analyze the data using statistical, geospatial and network analysis to assess associations between SPD marketing and specific risk factors for user groups. We will accomplish these objectives using a multidisciplinary approach that involves disciplines and methods from public health-epidemiology, substance abuse research, computation science, legal and policy analysis, and geospatial analysis. The project has the following specific aims: Aim 1: Conduct digital surveillance of popular social media platforms Twitter and Instagram in order to describe the nature and magnitude of online marketing, sale and distribution of SPDs; Aim 2: Characterize the types of marketing strategies used by SPD vendors and drug dealers on these platforms, including marketing messages used to influence knowledge, attitudes and perceptions pertaining to SPDs and identification of the users and networks they target; Aim 3: Using statistical, network and geospatial methods, describe, test, and visualize associations between SPD marketing and distribution and specific risk factors and user groups. This is a critical opportunity to better understand how social media contributes to a growing ?digital? risk environment that can influence user initiation and enable illegal access to SPDs. Though research examining the linkages between social media and substance abuse has been growing, no study has specifically examined online marketing and access characteristics on more than one platform while at the same time assessing how geographic and user network factors can impact this unique and largely unregulated risk environment. Results from this study can generate further study hypotheses on the association between SPD behavioral risk factors and SPD product trends, while also informing future interventions utilizing e-health tools including targeted regulation, health education, and counter-marketing.